In the field of semiconductor, a semiconductor device is conventionally manufactured by applying various processing steps to a wafer.
In the semiconductor device manufacturing process, a particle-less and chemical component-less transfer environment of a wafer has been required, and a closed type container called an FOUP (Front-Opening Unified Pod) and a transfer chamber generally called an EFEM (Equipment Front End Module) which transfers a wafer to or from a processing device are used (see the following Patent Literature 1). In the transfer chamber, usually, fresh outside air in a clean room is taken into an FFU (Fun Filter Unit) installed in an upper part, and the air is made to flow downward inside of the transfer chamber and exhausted to the outside from a floor surface, so as to stably obtain a constant clean atmosphere.
Further, as the semiconductor device structure decreases in size recently, influences caused by the moisture content, oxygen, chemical components, and so forth affecting the semiconductor device structure are becoming a more serious problem. To address this problem, replacing the inside of the transfer chamber with N2 (nitrogen) gas which is inactive gas, and transferring a wafer under an N2 atmosphere have been proposed. In that case, in order to reduce consumption of N2 gas and to suppress running cost, since it is necessary to keep the inside clean while reducing the supply amount of fresh N2 gas, it is possible to make N2 gas circulate while passing through a filter.
Further, it is possible to provide a chemical filter to efficiently remove chemical components from the circulating N2 gas. Since chemical components can be carried into the transfer chamber with a wafer which is subjected to a process treatment by the processing device, it is possible to efficiently remove such chemical components by using a chemical filter as a gas processing device and keep a further cleaner atmosphere.